A generator set, or genset, generally comprises a primary power source, such as an internal combustion engine, or the like, as well as an electric machine, such as induction generators, switched reluctance generators, or any other suitable electric machine commonly employed to convert mechanical energy, or other forms of energy, into electrical energy. In typical implementations, one or more gensets are arranged to communicate generated electrical energy through a shared or common bus that is further supplied to one or more connected loads. The power output by each of the gensets may be individually controlled and monitored by a central control system, which may adjust genset control based on detected changes in load or load demand.
Conventional control systems also provide a failsafe condition or a fallback control scheme for error conditions, such as when there is a loss of communication between one or more of the gensets. In such a failsafe condition, one or more of the gensets operated as droop gensets are automatically placed under a droop control scheme and operated separately from the other gensets operating under an isochronous control scheme. As shown for example in the prior art embodiment of FIG. 1, the isochronous gensets are maintained at nominal, fixed operating frequencies which handle the bulk of the load demand, while the droop gensets are limited to the operating frequencies of the isochronous gensets and set to a predefined target load, such as 50% load, or the like.
This limited flexibility of the droop gensets can introduce several setbacks when the gensets switch in and out of failsafe conditions. For instance, if the droop gensets were operating at a different load percentage immediately prior to entering the failsafe condition, each droop genset would have to abruptly shift its frequency and load point to those dictated by the droop control scheme, as shown in FIG. 1, upon entering the failsafe condition. The abrupt change in genset operation may cause instability in the overall system and a loss of power synchronization. In addition, the droop control scheme does not allow for a more even distribution of loads among the gensets. Under conventional failsafe control schemes, for instance, the isochronous gensets may be allowed to become overloaded even while the droop gensets are underloaded.
The present disclosure is directed at addressing one or more of the deficiencies set forth above.